Multi Node & Extension objects

In a multi node (2 Node) environment, if you have a network load balancer, my understanding is it will direct you to one of the Sense nodes. If I have 2 identical nodes (Fail over) and the central node goes down, I should be directed to the 2nd node. Is this correct so far? Also, I have installed extensions on the central node and node 2, however if the central node is down I am not able to use the extensions on Node 2 and I am getting this error,